It's hard to to judge because most of Marvel's Star Wars covers haven't had anything to do with the actual content of the book.
They've just published synopsis for a number of young reader novels. Most appear to be set between SW and ESB:
Lost Stars
This thrilling Young Adult novel gives readers a macro view of some of the most important events in the Star Wars universe, from the rise of the Rebellion to the fall of the Empire. Readers will experience these major moments through the eyes of two childhood friends–Ciena Ree and Thane Kyrell–who have grown up to become an Imperial officer and a Rebel pilot. Now on opposite sides of the war, will these two star-crossed lovers reunite, or will duty tear them–and the galaxy–apart.
Star Wars: Lost Stars also includes all-new post-Star Wars: Return of the Jedi content, as well as hints and clues about the upcoming film Star Wars: The Force Awakens, making this a must-read for all Star Wars fans.
The Weapon of a Jedi: A Luke Skywalker Adventure
Luke Skywalker returns for an all-new adventure in this thrilling upper middle grade novel. Set between Star Wars: A New Hope and Star Wars: The Empire Strikes Back, the story finds Luke Skywalker, C-3PO, and R2-D2 stranded on a mysterious planet, and explores Luke’s first-ever duel with a lightsaber. Hidden in the story are also clues and hints about the upcoming film Star Wars: The Force Awakens, making this a must-read for fans old and new!
Moving Target: A Princess Leia Adventure
Princess Leia returns for an all-new adventure in this thrilling upper middle grade novel. Set between Star Wars: The Empire Strikes Back and Star Wars: The Return of the Jedi, the story follows the warrior princess as she leads a ragtag group of rebels on a dangerous mission against the evil Galactic Empire. Hidden in the story are also hints and clues about the upcoming film Star Wars: The Force Awakens, making this a must-read for fans old and new!
Smuggler's Run: A Han Solo Adventure
Han Solo and Chewbacca the Wookiee team-up for an all-new adventure in this thrilling upper middle grade novel. Set between Star Wars: A New Hope and Star Wars: The Empire Strikes Back, the story follows everyone’s favorite pair of smugglers as they fly the Millennium Falcon on a top-secret mission for the Rebellion. Hidden in the story are also hints and clues about the upcoming film, Star Wars: The Force Awakens, making this a must-read for fans old and new!